Daisy Chain Assembly Formed from a Cucurbit[6]uril Derivative

The building block synthesis of a derivative of CB[6] that bears a reactive propargyloxy group and its functionalization by click chemistry to yield <b>1</b> which contains a covalently attached isobutylammonium group is presented. Compound <b>1</b> undergoes self-assembly to yield a cyclic [c2] daisy chain assembly (<b>1</b>₂) in water. The behavior of <b>1</b>₂ in response to various stimuli (e.g., guests and CB[<i>n</i>] receptors) is described

Absolute and relative binding affinity of cucurbit[7]uril towards a series of cationic guests

<div><p>We determined the relative binding constants (<i>K</i>_rel) for guests <b>1</b>–<b>19</b> towards cucurbit[7]uril by ¹H NMR competition experiments in 100 mM Na₃PO₄-buffered D₂O. In these experiments, we use guest <b>11</b> as the reference guest because of its strong binding towards CB[7] and its advantageous spectroscopic properties (e.g. slow exchange on NMR timescale and distinct resonances for key protons). To convert the determined <i>K</i>_rel values to absolute binding constants, we performed a direct UV–vis titration of <b>1</b> with CB[7] to determine <i>K</i>_a for CB[7]√<b>1</b>. The trends in the determined values of <i>K</i>_rel and <i>K</i>_a are discussed with respect to the importance of the concentration of metal ions in the buffer, the influence of hydroxyl groups located at the portals or inside the CB[7] cavity, geometry of the guest (e.g. regioisomers), the number of guest C atoms and secondary electrostatic interactions.</p></div

Multiscale Investigation of Moisture-Induced Structural Evolution in Asphalt–Aggregate Interfaces and Analysis of the Relevant Chemical Relationship Using Atomic Force Microscopy and Molecular Dynamics

Chemical changes and intermolecular interactions in asphalt dominate the molecular reorganization and cause the evolution of micro- and mesostructures. Given the lack of knowledge regarding the molecular chemistry–microstructure relationship of the asphalt–aggregate interface, the moisture-induced adhesive failure occurring at this interface has not been fully understood. This study investigates the multiscale structures of the asphalt–aggregate interfaces exposed to water and establishes the relationship between the structures and molecular interactions. The meso- and micromorphologies of two types of treated interfacial asphalts were observed via optical microscopy and atomic force microscopy. The results show an undulated surface and boundary retreat in asphalts because of the overall interfacial tension. Dispersed microbumps measuring tens of nanometers in height progressively grow until they merge into large bumps with increasing water exposure depending on the types of asphalt and aggregates. Fourier transform infrared (FTIR) spectrometry results show enriched polar components at the surface of the treated interfacial asphalt and water diffusion driven by complex intermolecular forces. The molecular behavior simulated by molecular dynamics calculations reveals that aliphatic molecules amalgamate into nonpolar clusters, while polar molecules migrate out and act as a surfactant to stabilize the asphalt–water system driven by the interfacial tension gradient. Internal coalescence of nonpolar components results in protrusion of the asphalt’s surface, and the migration of polar components to the surface accounts for the increased absorption peaks of the polar groups. This phenomenon could explain the FTIR spectra and formation of microbumps. The state of absorbed water and nanostructures of the interfacial asphalt are dominated by intermolecular interactions among asphalt, water, and aggregates. This study provides deep insights into the structural evolution of asphalt from the chemical and molecular perspectives

Sensor for Nitrophenol Based on a Fluorescent Molecular Clip

We report the synthesis, X-ray crystal structure, and photophysics of a fluorescent molecular clip (1). Binding studies of 1 toward phenols 2a−j were carried out using fluorescence, 1H NMR, and IR spectroscopy, which revealed a high affinity and selectivity for 4-nitrophenol (2a) due to formation of the 1·2a complex driven by H-bonding and π−π stacking interactions

Sensor for Nitrophenol Based on a Fluorescent Molecular Clip

We report the synthesis, X-ray crystal structure, and photophysics of a fluorescent molecular clip (1). Binding studies of 1 toward phenols 2a−j were carried out using fluorescence, 1H NMR, and IR spectroscopy, which revealed a high affinity and selectivity for 4-nitrophenol (2a) due to formation of the 1·2a complex driven by H-bonding and π−π stacking interactions

MOESM1 of IFN-γ down-regulates the PD-1 expression and assist nivolumab in PD-1-blockade effect on CD8+ T-lymphocytes in pancreatic cancer

Additional file 1: Figure S1. The average tumor sizes of 0.1 μg/ml mAb-IFN-γ, IFN-γ, 0.1 μg/ml mAb and Ctrl groups on 31 days after the injection of BxPC-3 cells

Table1_Analysis of the risk factors for secondary hemorrhage after abdominal surgery.xls

IntroductionThis study aimed to conduct a clinical review and analysis to recommend options for the prevention and treatment of postoperative hemorrhage.Patients and MethodsA total of 138 patients who experienced postoperative hemorrhage after abdominal surgery in the period between January 2015 and December 2020 at the Sir Run Run Shaw Hospital, affiliated to Zhejiang University School of Medicine, participated in this study. They were divided into a group with primary bleeding only and a secondary bleeding group. Univariate and multivariate statistical analyses were performed, followed by plotting of cumulative hazard and survival curves for the two groups.ResultsThe main factors of interest found to be associated with secondary hemorrhage were duration of the operation, the time of the first bleeding incident, intervention time, performance of combined organ resection, use of surgical intervention, occurrence of abdominal infection, admission to the intensive care unit (ICU), postoperative length of stay, and total hospitalization expenses. Among these, a long operative duration (>5 h) and an extended intervention time (>5 h) were identified as independent predictors of risk of secondary hemorrhage.ConclusionsSecondary hemorrhage after abdominal surgery is mainly associated with subjective human factors, and it is an important cause of poor prognosis and even death. Proper reductions in operation time and implementation of a quick response to bleeding are the key factors in tackling bleeding. Further reduction in the rates of postoperative hemorrhage and mortality will require a concerted effort by surgeons in terms of both intraoperative surgical techniques and postoperative management.</p

Tetraphenylethene-Based Platinum(II) Bis-Triangular Dicycles with Tunable Emissions

Tunable luminescent materials have attracted considerable interest for their wide applications in electronic optical devices, biological probes and sensors, tunable displays, and security technologies. Herein, we describe a strategy of coordination-driven self-assembly in order to prepare discrete tetraphenylethene-based platinum­(II) bis-triangular dicycles 1 and 2 with aggregation-induced emission properties. The X-ray structure confirms that they possess two triangular cavities in which free rotation of the central TPE unit is restricted. As a kind of fluorescent material, the AIE-active dicycles have good emissions with wide tunability based on their aggregate states by changing different solvents, adjusting the temperature, or combining them with other dyes (e.g., perylene) via a co-assembly process

Novel and Direct Transformation of Methyl Ketones or Carbinols to Primary Amides by Employing Aqueous Ammonia

A novel and direct transformation of aryl, heteroaryl, vinyl, or ethynyl methyl ketones or carbinols to corresponding primary amides has been developed. An iodine-NH3·H2O system was proven to be efficient for this reaction and afforded the expected products with good yields in aqueous media. A tandem Lieben−Haller−Bauer reaction mechanism was involved in this type of reaction and is proposed for the first time

Molecular data confirm Monolepta hieroglyphica (Motschulsky, 1858) and M. quadriguttata (Motschulsky, 1860) being synonyms of M. signata (Oliver, 1808)

Monolepta hieroglyphica (Motschulsky, 1858) has been recently revised as the synonym of M. signata (Oliver, 1808) based on morphological characteristics. M. quadriguttata (Motschulsky, 1860) was synonymized with M. signata over 100 years ago. However, this synonymy has not be confirmed by molecular data. This widely distributed and abundant species shows a high variability in coloration patterns that caused numbers of synonyms. We selected color forms typical for the three nominal taxa for phylogenetic analysis. The phylogenetic, haplotype and genetic differentiation analysis of M. hieroglyphica, M. quadriguttata and M. signata were constructed to determine the relationships between them, and we also found mating behavior between them. They were intermixed together on phylogenetic trees, and M. hieroglyphica and M. quadriguttata had shared haplotype. There was no significant difference among them for genetic distance, and the synonymy of the three names based on external and genital characters can be confirmed by molecular data. </p